Total Complexity | 110 |
Total Lines | 607 |
Duplicated Lines | 0 % |
Changes | 0 |
Complex classes like HTMLPurifier_Encoder often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use HTMLPurifier_Encoder, and based on these observations, apply Extract Interface, too.
1 | <?php |
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7 | class HTMLPurifier_Encoder |
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8 | { |
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9 | |||
10 | /** |
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11 | * Constructor throws fatal error if you attempt to instantiate class |
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12 | */ |
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13 | private function __construct() |
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14 | { |
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15 | trigger_error('Cannot instantiate encoder, call methods statically', E_USER_ERROR); |
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16 | } |
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17 | |||
18 | /** |
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19 | * Error-handler that mutes errors, alternative to shut-up operator. |
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20 | */ |
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21 | public static function muteErrorHandler() |
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23 | } |
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24 | |||
25 | /** |
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26 | * iconv wrapper which mutes errors, but doesn't work around bugs. |
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27 | * @param string $in Input encoding |
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28 | * @param string $out Output encoding |
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29 | * @param string $text The text to convert |
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30 | * @return string |
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31 | */ |
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32 | public static function unsafeIconv($in, $out, $text) |
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33 | { |
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34 | set_error_handler(array('HTMLPurifier_Encoder', 'muteErrorHandler')); |
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35 | $r = iconv($in, $out, $text); |
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36 | restore_error_handler(); |
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37 | return $r; |
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38 | } |
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39 | |||
40 | /** |
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41 | * iconv wrapper which mutes errors and works around bugs. |
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42 | * @param string $in Input encoding |
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43 | * @param string $out Output encoding |
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44 | * @param string $text The text to convert |
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45 | * @param int $max_chunk_size |
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46 | * @return string |
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47 | */ |
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48 | public static function iconv($in, $out, $text, $max_chunk_size = 8000) |
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95 | } |
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96 | } |
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97 | |||
98 | /** |
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99 | * Cleans a UTF-8 string for well-formedness and SGML validity |
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100 | * |
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101 | * It will parse according to UTF-8 and return a valid UTF8 string, with |
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102 | * non-SGML codepoints excluded. |
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103 | * |
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104 | * Specifically, it will permit: |
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105 | * \x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF} |
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106 | * Source: https://www.w3.org/TR/REC-xml/#NT-Char |
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107 | * Arguably this function should be modernized to the HTML5 set |
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108 | * of allowed characters: |
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109 | * https://www.w3.org/TR/html5/syntax.html#preprocessing-the-input-stream |
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110 | * which simultaneously expand and restrict the set of allowed characters. |
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111 | * |
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112 | * @param string $str The string to clean |
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113 | * @param bool $force_php |
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114 | * @return string |
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115 | * |
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116 | * @note Just for reference, the non-SGML code points are 0 to 31 and |
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117 | * 127 to 159, inclusive. However, we allow code points 9, 10 |
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118 | * and 13, which are the tab, line feed and carriage return |
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119 | * respectively. 128 and above the code points map to multibyte |
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120 | * UTF-8 representations. |
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121 | * |
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122 | * @note Fallback code adapted from utf8ToUnicode by Henri Sivonen and |
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123 | * [email protected] at <http://iki.fi/hsivonen/php-utf8/> under the |
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124 | * LGPL license. Notes on what changed are inside, but in general, |
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125 | * the original code transformed UTF-8 text into an array of integer |
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126 | * Unicode codepoints. Understandably, transforming that back to |
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127 | * a string would be somewhat expensive, so the function was modded to |
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128 | * directly operate on the string. However, this discourages code |
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129 | * reuse, and the logic enumerated here would be useful for any |
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130 | * function that needs to be able to understand UTF-8 characters. |
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131 | * As of right now, only smart lossless character encoding converters |
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132 | * would need that, and I'm probably not going to implement them. |
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133 | */ |
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134 | public static function cleanUTF8($str, $force_php = false) |
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135 | { |
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136 | // UTF-8 validity is checked since PHP 4.3.5 |
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137 | // This is an optimization: if the string is already valid UTF-8, no |
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138 | // need to do PHP stuff. 99% of the time, this will be the case. |
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139 | if (preg_match( |
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140 | '/^[\x{9}\x{A}\x{D}\x{20}-\x{7E}\x{A0}-\x{D7FF}\x{E000}-\x{FFFD}\x{10000}-\x{10FFFF}]*$/Du', |
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141 | $str |
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142 | )) { |
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143 | return $str; |
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144 | } |
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145 | |||
146 | $mState = 0; // cached expected number of octets after the current octet |
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147 | // until the beginning of the next UTF8 character sequence |
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148 | $mUcs4 = 0; // cached Unicode character |
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149 | $mBytes = 1; // cached expected number of octets in the current sequence |
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150 | |||
151 | // original code involved an $out that was an array of Unicode |
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152 | // codepoints. Instead of having to convert back into UTF-8, we've |
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153 | // decided to directly append valid UTF-8 characters onto a string |
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154 | // $out once they're done. $char accumulates raw bytes, while $mUcs4 |
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155 | // turns into the Unicode code point, so there's some redundancy. |
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156 | |||
157 | $out = ''; |
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158 | $char = ''; |
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159 | |||
160 | $len = strlen($str); |
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161 | for ($i = 0; $i < $len; $i++) { |
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162 | $in = ord($str[$i]); |
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163 | $char .= $str[$i]; // append byte to char |
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164 | if (0 == $mState) { |
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165 | // When mState is zero we expect either a US-ASCII character |
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166 | // or a multi-octet sequence. |
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167 | if (0 == (0x80 & ($in))) { |
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168 | // US-ASCII, pass straight through. |
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169 | if (($in <= 31 || $in == 127) && |
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170 | !($in == 9 || $in == 13 || $in == 10) // save \r\t\n |
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171 | ) { |
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172 | // control characters, remove |
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173 | } else { |
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174 | $out .= $char; |
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175 | } |
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176 | // reset |
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177 | $char = ''; |
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178 | $mBytes = 1; |
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179 | } elseif (0xC0 == (0xE0 & ($in))) { |
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180 | // First octet of 2 octet sequence |
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181 | $mUcs4 = ($in); |
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182 | $mUcs4 = ($mUcs4 & 0x1F) << 6; |
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183 | $mState = 1; |
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184 | $mBytes = 2; |
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185 | } elseif (0xE0 == (0xF0 & ($in))) { |
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186 | // First octet of 3 octet sequence |
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187 | $mUcs4 = ($in); |
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188 | $mUcs4 = ($mUcs4 & 0x0F) << 12; |
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189 | $mState = 2; |
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190 | $mBytes = 3; |
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191 | } elseif (0xF0 == (0xF8 & ($in))) { |
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192 | // First octet of 4 octet sequence |
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193 | $mUcs4 = ($in); |
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194 | $mUcs4 = ($mUcs4 & 0x07) << 18; |
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195 | $mState = 3; |
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196 | $mBytes = 4; |
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197 | } elseif (0xF8 == (0xFC & ($in))) { |
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198 | // First octet of 5 octet sequence. |
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199 | // |
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200 | // This is illegal because the encoded codepoint must be |
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201 | // either: |
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202 | // (a) not the shortest form or |
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203 | // (b) outside the Unicode range of 0-0x10FFFF. |
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204 | // Rather than trying to resynchronize, we will carry on |
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205 | // until the end of the sequence and let the later error |
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206 | // handling code catch it. |
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207 | $mUcs4 = ($in); |
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208 | $mUcs4 = ($mUcs4 & 0x03) << 24; |
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209 | $mState = 4; |
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210 | $mBytes = 5; |
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211 | } elseif (0xFC == (0xFE & ($in))) { |
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212 | // First octet of 6 octet sequence, see comments for 5 |
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213 | // octet sequence. |
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214 | $mUcs4 = ($in); |
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215 | $mUcs4 = ($mUcs4 & 1) << 30; |
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216 | $mState = 5; |
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217 | $mBytes = 6; |
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218 | } else { |
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219 | // Current octet is neither in the US-ASCII range nor a |
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220 | // legal first octet of a multi-octet sequence. |
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221 | $mState = 0; |
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222 | $mUcs4 = 0; |
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223 | $mBytes = 1; |
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224 | $char = ''; |
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225 | } |
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226 | } else { |
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227 | // When mState is non-zero, we expect a continuation of the |
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228 | // multi-octet sequence |
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229 | if (0x80 == (0xC0 & ($in))) { |
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230 | // Legal continuation. |
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231 | $shift = ($mState - 1) * 6; |
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232 | $tmp = $in; |
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233 | $tmp = ($tmp & 0x0000003F) << $shift; |
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234 | $mUcs4 |= $tmp; |
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235 | |||
236 | if (0 == --$mState) { |
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237 | // End of the multi-octet sequence. mUcs4 now contains |
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238 | // the final Unicode codepoint to be output |
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239 | |||
240 | // Check for illegal sequences and codepoints. |
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241 | |||
242 | // From Unicode 3.1, non-shortest form is illegal |
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243 | if (((2 == $mBytes) && ($mUcs4 < 0x0080)) || |
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244 | ((3 == $mBytes) && ($mUcs4 < 0x0800)) || |
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245 | ((4 == $mBytes) && ($mUcs4 < 0x10000)) || |
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246 | (4 < $mBytes) || |
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247 | // From Unicode 3.2, surrogate characters = illegal |
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248 | (($mUcs4 & 0xFFFFF800) == 0xD800) || |
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249 | // Codepoints outside the Unicode range are illegal |
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250 | ($mUcs4 > 0x10FFFF) |
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251 | ) { |
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252 | |||
253 | } elseif (0xFEFF != $mUcs4 && // omit BOM |
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254 | // check for valid Char unicode codepoints |
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255 | ( |
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256 | 0x9 == $mUcs4 || |
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257 | 0xA == $mUcs4 || |
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258 | 0xD == $mUcs4 || |
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259 | (0x20 <= $mUcs4 && 0x7E >= $mUcs4) || |
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260 | // 7F-9F is not strictly prohibited by XML, |
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261 | // but it is non-SGML, and thus we don't allow it |
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262 | (0xA0 <= $mUcs4 && 0xD7FF >= $mUcs4) || |
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263 | (0xE000 <= $mUcs4 && 0xFFFD >= $mUcs4) || |
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264 | (0x10000 <= $mUcs4 && 0x10FFFF >= $mUcs4) |
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265 | ) |
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266 | ) { |
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267 | $out .= $char; |
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268 | } |
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269 | // initialize UTF8 cache (reset) |
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270 | $mState = 0; |
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271 | $mUcs4 = 0; |
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272 | $mBytes = 1; |
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273 | $char = ''; |
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274 | } |
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275 | } else { |
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276 | // ((0xC0 & (*in) != 0x80) && (mState != 0)) |
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277 | // Incomplete multi-octet sequence. |
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278 | // used to result in complete fail, but we'll reset |
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279 | $mState = 0; |
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280 | $mUcs4 = 0; |
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281 | $mBytes = 1; |
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282 | $char =''; |
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283 | } |
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284 | } |
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285 | } |
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286 | return $out; |
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287 | } |
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288 | |||
289 | /** |
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290 | * Translates a Unicode codepoint into its corresponding UTF-8 character. |
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291 | * @note Based on Feyd's function at |
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292 | * <http://forums.devnetwork.net/viewtopic.php?p=191404#191404>, |
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293 | * which is in public domain. |
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294 | * @note While we're going to do code point parsing anyway, a good |
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295 | * optimization would be to refuse to translate code points that |
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296 | * are non-SGML characters. However, this could lead to duplication. |
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297 | * @note This is very similar to the unichr function in |
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298 | * maintenance/generate-entity-file.php (although this is superior, |
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299 | * due to its sanity checks). |
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300 | */ |
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301 | |||
302 | // +----------+----------+----------+----------+ |
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303 | // | 33222222 | 22221111 | 111111 | | |
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304 | // | 10987654 | 32109876 | 54321098 | 76543210 | bit |
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305 | // +----------+----------+----------+----------+ |
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306 | // | | | | 0xxxxxxx | 1 byte 0x00000000..0x0000007F |
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307 | // | | | 110yyyyy | 10xxxxxx | 2 byte 0x00000080..0x000007FF |
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308 | // | | 1110zzzz | 10yyyyyy | 10xxxxxx | 3 byte 0x00000800..0x0000FFFF |
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309 | // | 11110www | 10wwzzzz | 10yyyyyy | 10xxxxxx | 4 byte 0x00010000..0x0010FFFF |
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310 | // +----------+----------+----------+----------+ |
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311 | // | 00000000 | 00011111 | 11111111 | 11111111 | Theoretical upper limit of legal scalars: 2097151 (0x001FFFFF) |
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312 | // | 00000000 | 00010000 | 11111111 | 11111111 | Defined upper limit of legal scalar codes |
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313 | // +----------+----------+----------+----------+ |
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314 | |||
315 | public static function unichr($code) |
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357 | } |
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358 | |||
359 | /** |
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360 | * @return bool |
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361 | */ |
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362 | public static function iconvAvailable() |
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369 | } |
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370 | |||
371 | /** |
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372 | * Convert a string to UTF-8 based on configuration. |
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373 | * @param string $str The string to convert |
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374 | * @param HTMLPurifier_Config $config |
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375 | * @param HTMLPurifier_Context $context |
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376 | * @return string |
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377 | */ |
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378 | public static function convertToUTF8($str, $config, $context) |
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379 | { |
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380 | $encoding = $config->get('Core.Encoding'); |
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381 | if ($encoding === 'utf-8') { |
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382 | return $str; |
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383 | } |
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384 | static $iconv = null; |
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385 | if ($iconv === null) { |
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386 | $iconv = self::iconvAvailable(); |
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387 | } |
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388 | if ($iconv && !$config->get('Test.ForceNoIconv')) { |
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389 | // unaffected by bugs, since UTF-8 support all characters |
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390 | $str = self::unsafeIconv($encoding, 'utf-8//IGNORE', $str); |
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391 | if ($str === false) { |
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392 | // $encoding is not a valid encoding |
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393 | trigger_error('Invalid encoding ' . $encoding, E_USER_ERROR); |
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394 | return ''; |
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395 | } |
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396 | // If the string is bjorked by Shift_JIS or a similar encoding |
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397 | // that doesn't support all of ASCII, convert the naughty |
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398 | // characters to their true byte-wise ASCII/UTF-8 equivalents. |
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399 | $str = strtr($str, self::testEncodingSupportsASCII($encoding)); |
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400 | return $str; |
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401 | } elseif ($encoding === 'iso-8859-1' && function_exists('mb_convert_encoding')) { |
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402 | $str = mb_convert_encoding($str, 'UTF-8', 'ISO-8859-1'); |
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403 | return $str; |
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404 | } |
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405 | $bug = HTMLPurifier_Encoder::testIconvTruncateBug(); |
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406 | if ($bug == self::ICONV_OK) { |
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407 | trigger_error('Encoding not supported, please install iconv', E_USER_ERROR); |
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408 | } else { |
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409 | trigger_error( |
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410 | 'You have a buggy version of iconv, see https://bugs.php.net/bug.php?id=48147 ' . |
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411 | 'and http://sourceware.org/bugzilla/show_bug.cgi?id=13541', |
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412 | E_USER_ERROR |
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413 | ); |
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414 | } |
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415 | } |
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416 | |||
417 | /** |
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418 | * Converts a string from UTF-8 based on configuration. |
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419 | * @param string $str The string to convert |
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420 | * @param HTMLPurifier_Config $config |
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421 | * @param HTMLPurifier_Context $context |
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422 | * @return string |
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423 | * @note Currently, this is a lossy conversion, with unexpressable |
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424 | * characters being omitted. |
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425 | */ |
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426 | public static function convertFromUTF8($str, $config, $context) |
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427 | { |
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428 | $encoding = $config->get('Core.Encoding'); |
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429 | if ($escape = $config->get('Core.EscapeNonASCIICharacters')) { |
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430 | $str = self::convertToASCIIDumbLossless($str); |
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431 | } |
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432 | if ($encoding === 'utf-8') { |
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433 | return $str; |
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434 | } |
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435 | static $iconv = null; |
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436 | if ($iconv === null) { |
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437 | $iconv = self::iconvAvailable(); |
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438 | } |
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439 | if ($iconv && !$config->get('Test.ForceNoIconv')) { |
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440 | // Undo our previous fix in convertToUTF8, otherwise iconv will barf |
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441 | $ascii_fix = self::testEncodingSupportsASCII($encoding); |
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442 | if (!$escape && !empty($ascii_fix)) { |
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443 | $clear_fix = array(); |
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444 | foreach ($ascii_fix as $utf8 => $native) { |
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445 | $clear_fix[$utf8] = ''; |
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446 | } |
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447 | $str = strtr($str, $clear_fix); |
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448 | } |
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449 | $str = strtr($str, array_flip($ascii_fix)); |
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450 | // Normal stuff |
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451 | $str = self::iconv('utf-8', $encoding . '//IGNORE', $str); |
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452 | return $str; |
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453 | } elseif ($encoding === 'iso-8859-1' && function_exists('mb_convert_encoding')) { |
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454 | $str = mb_convert_encoding($str, 'ISO-8859-1', 'UTF-8'); |
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455 | return $str; |
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456 | } |
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457 | trigger_error('Encoding not supported', E_USER_ERROR); |
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458 | // You might be tempted to assume that the ASCII representation |
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459 | // might be OK, however, this is *not* universally true over all |
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460 | // encodings. So we take the conservative route here, rather |
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461 | // than forcibly turn on %Core.EscapeNonASCIICharacters |
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462 | } |
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463 | |||
464 | /** |
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465 | * Lossless (character-wise) conversion of HTML to ASCII |
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466 | * @param string $str UTF-8 string to be converted to ASCII |
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467 | * @return string ASCII encoded string with non-ASCII character entity-ized |
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468 | * @warning Adapted from MediaWiki, claiming fair use: this is a common |
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469 | * algorithm. If you disagree with this license fudgery, |
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470 | * implement it yourself. |
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471 | * @note Uses decimal numeric entities since they are best supported. |
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472 | * @note This is a DUMB function: it has no concept of keeping |
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473 | * character entities that the projected character encoding |
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474 | * can allow. We could possibly implement a smart version |
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475 | * but that would require it to also know which Unicode |
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476 | * codepoints the charset supported (not an easy task). |
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477 | * @note Sort of with cleanUTF8() but it assumes that $str is |
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478 | * well-formed UTF-8 |
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479 | */ |
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480 | public static function convertToASCIIDumbLossless($str) |
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510 | } |
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511 | |||
512 | /** No bugs detected in iconv. */ |
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513 | const ICONV_OK = 0; |
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514 | |||
515 | /** Iconv truncates output if converting from UTF-8 to another |
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516 | * character set with //IGNORE, and a non-encodable character is found */ |
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517 | const ICONV_TRUNCATES = 1; |
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518 | |||
519 | /** Iconv does not support //IGNORE, making it unusable for |
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520 | * transcoding purposes */ |
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521 | const ICONV_UNUSABLE = 2; |
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522 | |||
523 | /** |
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524 | * glibc iconv has a known bug where it doesn't handle the magic |
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525 | * //IGNORE stanza correctly. In particular, rather than ignore |
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526 | * characters, it will return an EILSEQ after consuming some number |
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527 | * of characters, and expect you to restart iconv as if it were |
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528 | * an E2BIG. Old versions of PHP did not respect the errno, and |
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529 | * returned the fragment, so as a result you would see iconv |
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530 | * mysteriously truncating output. We can work around this by |
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531 | * manually chopping our input into segments of about 8000 |
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532 | * characters, as long as PHP ignores the error code. If PHP starts |
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533 | * paying attention to the error code, iconv becomes unusable. |
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534 | * |
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535 | * @return int Error code indicating severity of bug. |
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536 | */ |
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537 | public static function testIconvTruncateBug() |
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538 | { |
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539 | static $code = null; |
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540 | if ($code === null) { |
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541 | // better not use iconv, otherwise infinite loop! |
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542 | $r = self::unsafeIconv('utf-8', 'ascii//IGNORE', "\xCE\xB1" . str_repeat('a', 9000)); |
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543 | if ($r === false) { |
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544 | $code = self::ICONV_UNUSABLE; |
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545 | } elseif (($c = strlen($r)) < 9000) { |
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546 | $code = self::ICONV_TRUNCATES; |
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547 | } elseif ($c > 9000) { |
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548 | trigger_error( |
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549 | 'Your copy of iconv is extremely buggy. Please notify HTML Purifier maintainers: ' . |
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550 | 'include your iconv version as per phpversion()', |
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551 | E_USER_ERROR |
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552 | ); |
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553 | } else { |
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554 | $code = self::ICONV_OK; |
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555 | } |
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556 | } |
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557 | return $code; |
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558 | } |
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559 | |||
560 | /** |
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561 | * This expensive function tests whether or not a given character |
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562 | * encoding supports ASCII. 7/8-bit encodings like Shift_JIS will |
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563 | * fail this test, and require special processing. Variable width |
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564 | * encodings shouldn't ever fail. |
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565 | * |
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566 | * @param string $encoding Encoding name to test, as per iconv format |
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567 | * @param bool $bypass Whether or not to bypass the precompiled arrays. |
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568 | * @return Array of UTF-8 characters to their corresponding ASCII, |
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569 | * which can be used to "undo" any overzealous iconv action. |
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570 | */ |
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571 | public static function testEncodingSupportsASCII($encoding, $bypass = false) |
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614 | } |
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615 | } |
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616 | |||
617 | // vim: et sw=4 sts=4 |
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618 |